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Shantilal Shah Engineering College, Bhavnagar
General Department
Physics (Practical)-3110011
Index
Sr.
No. Code Objective
Page
no. Date Sign Remarks
1 P_1
To Determination of the velocity of
ultrasonic waves in a non-electrolytic liquid
by ultrasonic interferometer.
1 - 3
2 P_2
(VLAB)
To determine the frequency of an
electrically maintained tuning fork by,
1. Transverse mode of vibration
2. Longitudinal mode of vibration
4 - 7
3 P_3 To find reverberation time using Sabin’s
formula. 8 - 10
4 P_4
(VLAB)
To determine the wavelength of the given
source using Newton’s ring. 11 - 12
5 P_5
Understand the function of CRO and
measure the rms voltage ns frequency of AC
signal using CRO.
13 - 14
6 P_6
(VLAB)
To determine the moment of inertia of the
given disc using Torsion pendulum, with
identical masses.
15 - 16
7 P_7 Measurement of the distance using
ultrasonic sensors 17 - 17
Sr.
No. Code Tutorial no.
Page
no. Date Sign Marks
8 T_1 Tutorial - 1
9 T_2 Tutorial - 2
10 T_3 Tutorial - 3
11 T_4 Tutorial - 4
12 T_5 Tutorial - 5
13 T_6 Tutorial - 6
1
Shantilal Shah Engineering College, Bhavnagar
Physics Laboratory Manual
Experiment-1 (P_1)
Objective: Determination of the velocity of ultrasonic waves in a non-electrolytic liquid
by ultrasonic interferometer.
Item Required: Ultrasonic Measurement Lab Trainer, Liquid cell, Mains Cord, Co-axial
cable
Procedure:
1. Connect the mains cord to the Trainer.
2. Insert the cell in the base and clamp it with the help of a screw provided on one of
its side.
3. Unscrew the knurled cap of cell and lift it away from double walled construction of
the cell. In the middle portion of it pour experimental liquid (water) and screw the
knurled caps as shown in figure 1.
4. Two chutes in double wall construction are provided for water circulation to
maintain desired temperature.
Note: Make sure the power switch should be ‘Off’ at the time of connection.
5. Connect co-axial cable between liquid cell and receiver terminal of Nvis 6109
Ultrasonic Measurement Lab Trainer.
Note: Set the gain knob at fully anticlockwise, before switch ‘On’ the trainer.
6. Switch ‘On’ the power of trainer.
7. Wait for 2-3 minutes until display shows a constant value of current (because for
better interference, some time is needed).
8. Adjust the gain knob for maximum constant value of current.
9. Move the micrometer slowly (by increments of 0.01mm) in either clockwise or
anticlockwise direction till the current shows minimum reading on meter.
10. Note the readings of micrometer corresponding to the value of current. Now again
rotate the micrometer in same direction until the second minimum value of current
occurred.
11. Note the readings of micrometer in the table below.
12. Repeat the same procedure for number of consecutive minima value of current and
tabulate them.
2
[Figure: Ultrasonic interferometer]
Observation Table:
Sr
No.
Current
(μA) Min
Micrometer Reading N(mm) Difference between
consecutive Max/Min
λ/2 = Nn+1 – Nn M.S.R C.S.R.
T.R.=M.S.R.+
(C.S.R.*L.C.)
1
2
3
4
5
6
7
8
9
10
3
Mean λ/2 =………………
⸫ Wavelength λ = ………….. mm = ……….. 10–3 m
Calculations:
Frequency f = 2MHz = 2 106 Hz
Therefore velocity of Ultrasonic wave in experimental liquid,
v = λ × f = ……………………………….. m/s
Result: The velocity of Ultrasonic wave in experimental liquid v = …………….. m/s.
4
Shantilal Shah Engineering College, Bhavnagar
Physics Laboratory Manual
Experiment-2 (P_2)
Aim: To determine the frequency of an electrically maintained tuning fork by,
1. Transverse mode of vibration
2. Longitudinal mode of vibration
Apparatus: Electrically maintained tuning fork, fine thread, scale pan, weights and
meter scale.
Transverse drive mode :
In this arrangement the vibrations of the prongs of the tuning fork are in the
direction perpendicular to the length of the string.
The time, during which the tuning fork completes one vibration, the string also
completes one vibration. In this mode, frequency of the string is equal to the
frequency of the tuning fork.
Frequency 24
gMf
l
Where the total mass M is equal to the mass M' of the weight in the scale pan plus the mass
M0 of the scale pane, M = M' + M0.
Linear density of string, 41.17 10Kg
m
Mass of the scale pan M0 = 0.5 gm
Longitudinal drive mode:
In this arrangement the tuning fork is set in such a manner that the vibrations of the
prongs are parallel to the length of the string.
The time, during which the tuning fork completes one vibration, the string completes
half of its vibration. In this mode, frequency of the fork is twice the frequency of the
string.
Frequency 2
gMf
l
5
Performing Simulator
Combo Box:
Longitudinal mode- In this arrangement the tuning fork is set in such a manner that the
vibrations of the prongs are parallel to the length of the string.
Transverse mode - In this arrangement the vibration of the prongs of the tuning fork are in
the direction perpendicular to the length of the string.
Selecting Tuning fork - There are five tuning forks with different frequencies. One can
choose any one of the tuning forks to carry out the experiment.
Select Environment- Use only earth’s environment.
Sliders:
Mass in the pan M'- This slider is used for adding mass in the scale pan.
Transformer Voltage- This is used to change the voltage of the step down transformer.
Note: At 8V, we get well defined loops.
Scale Position- This is used to change the position of the meter scale and one can calculate
the length of one loop.
Power On - This is used to start the experiment.
Pointer movement- The pointer can be moved by using the arrow keys on either side of the
zoomed part of the loop image in the simulator.
Reset- One can repeat the whole experiment by using this button.
Procedure for simulation
1. Select the mode of Vibration.
2. Select a particular tuning fork to carry out the experiment.
3. Choose the environment for doing the experiment.
4. The transformer voltage is adjusted to 8V.
5. Mass is suspended in the scale pan.
6. Power on the button and loops will be formed.
7. Length l for one loop is measured by adjusting the scale position.
8. Using equations for mode of vibration, calculate the frequency of particular tuning
fork.
9. Repeat the experiment by changing the parameters.
6
Observation Table
Mode of Vibration: Transverse Mass of the pan M0 = 0.5 gm
Tuning fork
Mass Suspended M
Kg
Total mass M in Kg (M+M0)
Number of Loops
N
Length of Loops (Total) L
Length of one Loop
LlN
Frequency in Hz f
1
2
3
4
5
Calculation of frequency: 24
gMf
l
7
Mode of Vibration: Longitudinal Mass of the pan M0 = 0.5 gm
Tuning fork
Mass Suspended M
Kg
Total mass M in Kg (M+M0)
Number of Loops
N
Length of Loops (Total) L
Length of one Loop
LlN
Frequency in Hz f
1
2
3
4
5
Calculation of frequency: 2
gMf
l
Result: (1) Frequency of tuning fork in transverse mode is = ........................Hz (2) Frequency of tuning fork in longitudinal mode is = ......................Hz
8
Shantilal Shah Engineering College, Bhavnagar
Physics Laboratory Manual
Experiment-3 (P_3)
Objective: To find reverberation time using sabin’s formula.
Item Required: Measurement tap.
Procedure:
1. Measure length, width and height in meter for given room.
2. Find volume of hall using V = l W h
3. Find area of each wall of the room.
4. Calculate reverberation time using following formula:
T = .
a
5. Repeat the same by considering all windows of room.
6. Repeat the same by considering all windows of room and carpet flooring and
gypsum ceiling.
Observations:
Length of room/hall, l = …………… m
Width of room/hall, W = …………. m
Height of room/hall, h = …………… m
Area of window, Sw = ……….. m2
Volume of the room/hall, V = ………………m3
Absorption coefficient of flooring tiles = 0.02 O.W.U m2
Absorption coefficient of concrete wall = 0.05 O.W.U m2
Absorption coefficient of wood = 0.08 O.W.U m2
Absorption coefficient of thick carpet = 0.65 O.W.U m2
Absorption coefficient of perforated Gypsum = 0.84 O.W.U m2
9
Observation Table:
Without Windows
Absorption of
walls, alS1
(O.W.U m2)
Absorption of
floor, a2S2
(O.W.U m2)
Absorption of
Ceiling, a3S3
(O.W.U m2)
Total Absorption,
ΣaS
(O.W.U m2)
Reverberation Time, T1
(s)
With wooden windows
Absorption of
walls, alS1
(O.W.U m2)
Absorption of
floor, a2S2
(O.W.U m2)
Absorption of
Ceiling, a3S3
(O.W.U m2)
Absorption of
Windows, awSw
(O.W.U m2)
Total Absorption,
ΣaS
(O.W.U m2)
Reverberation
Time, T2
(s)
Floor with carpet, Ceiling with perforated gypsum and wooden windows
Absorption of
walls, alS1
(O.W.U m2)
Absorption of
floor, a2S2
(O.W.U m2)
Absorption of
Ceiling, a3S3
(O.W.U m2)
Absorption of
Windows, awSw
(O.W.U m2)
Total Absorption,
ΣaS
(O.W.U m2)
Reverberation
Time, T3
(s)
Calculations:
(1) Without windows:
Total Absorption, ΣaS = a1S1 + a2S2 + a3S3 = ……………….. O.W.U. m2
Reverberation Time, T = .
10
(2) With windows:
Total Absorption, ΣaS = a1S1(without walls) + a2S2+ a3S3 + aWSW = ………O.W.U. m2
Reverberation Time, T = .
(3) Floor with carpet, ceiling with perforated gypsum and wooden windows:
Total Absorption, ΣaS = a1S1(without walls) + a2’S2‘+ a3’S3’ + aWSW = ……….. O.W.U. m2
Reverberation Time, T = .
Result:
1. The Reverberation time of given room/hall, T1 = …………….. s.
2. The Reverberation time of given room/hall with wooden window, T2 = …………….. s
3. The Reverberation time of given room/hall with wooden window and floor covered
with carpet and gypsum ceiling, T3 = …………….. s
11
Shantilal Shah Engineering College, Bhavnagar
Physics Laboratory Manual
Experiment-4 (P_4)
Aim: To determine the wavelength of the given source using Newton’s ring.
Components: Start button, Light source, Filter, Microscope, Lens, Medium and
Glass plate.
Equation: The wavelength of monochromatic light can be determined as
Where, Dm+p is the diameter of the (m+p)th dark ring and
Dm is the diameter of the mth dark ring.
R is radius of lens used
Variable region:
Choose Medium Combo box helps you to choose the type of medium that the
simulation have to perform.
Radius Slider helps to change the radius of curvature of lens.
The wavelength slider helps to change the wavelength of light used.
Measurement region:
The start button will help to play the simulation.
The variation in the rings can be seen when the medium, wavelength of light or
the radius of the lens changes.
Procedure:
Click on the "light on" button.
Select the lens of desirable radius.
Adjust the microscope position to view the Newton rings.
Focus the microscope to view the rings clearly.
Fix the cross-wire on 20th ring either from right or left of the centre dark ring and
take the readings.
Move the crosswire and take the reading of 18th, 16th...........2nd ring.
You have to take the reading of rings on either side of the centre dark ring.
Enter the readings in the tabular column.
Calculate the wavelength of the source by using the given formula.
12
Observations:
To find Least Count
1. One main scale division= ............... cm
2. Number of divisions on Vernier = ...............
3. L.C = One main scale division/ Number of division on vernier
=.................................
4. R= radius of lens = ……………………………….
Observation Table:
Sr.
No.
Order
of ring
Microscopic
Reading (cm) Diameter D
(cm)
D2
(cm2)
D2m+p -D2
m
(cm2) Left Right
1
2
3
4
5
6
7
8
9
10
Calculation:
Mean value of D2m+p - D
2m =.......cm2
Wavelength of light 2 2
4
m p mD D
pR
.............................nm
Result:
Wavelength of light from the given source is found to be = ……........... nm
13
Shantilal Shah Engineering College, Bhavnagar
Physics Laboratory Manual
Experiment-5 (P_5)
Aim: Understand the function of CRO and measure the rms voltage ns frequency of
AC signal using CRO.
Components: CRO, Function Generator
Procedure:
Switch on the CRO and Function Generator.
Study and understand the function of every knob on CRO and function generator.
Set function generator to any frequency with a particular peak to peak voltage
(VP)
Connect the output of function generator to any channel of CRO.
Adjust CRO so that stable and full signal is viewed.
Measure VP using formula-(1). Determine VP & Vrms.
Determine the frequency of the same signal.
Repeat for different signals.
Observation Table:
1. Measurement of AC voltage:
Sr.
No. Signal no.
Division on
Y-axis Volt/div. VP Vrms
1 Signal-1
2 Signal-2
3 Signal-3
14
2. Measurement of AC frequency:
Sr.
No. Signal no.
Division on
X-axis Time/div.
Time Period
(T)
Frequency
(f)
1 Signal-1
2 Signal-2
3 Signal-3
Calculation: 1. Signal-1
Voltage (VP) = (Division on Y-axis) (volt/division) = ....................
Vrms = 0.707 VP =......................
Time period (T) = (Division on X-axis) (time/division) = .....................
Frequency (f) =.....................
2. Signal-1 Voltage (VP) = (Division on Y-axis) (volt/division) = ....................
Vrms = 0.707 VP =......................
Time period (T) = (Division on X-axis) (time/division) = .....................
Frequency (f) =.....................
3. Signal-1
Voltage (VP) = (Division on Y-axis) (volt/division) = ....................
Vrms = 0.707 VP =......................
Time period (T) = (Division on X-axis) (time/division) = .....................
Frequency (f) =....................
Result:
With the help of CRO one can determine the rms voltage and frequency of AC signal.
15
Shantilal Shah Engineering College, Bhavnagar
Physics Laboratory Manual
Experiment-6 (P_6)
Aim: To determine the moment of inertia of the given disc using Torsion pendulum,
with identical masses.
Components: The given torsion pendulum, two identical cylindrical masses, stop
watch, metre scale, etc.
Procedure:
1. The radius of the suspension wire is measured using a screw gauge.
2. The length of the suspension wire is adjusted to suitable values like 0.3 m, 0.4 m,
0.5 m, .....0.9 m, 1 m etc.
3. The disc is set in oscillation. Find the time for 20 oscillations twice and determine
the mean period of oscillation ' T0 '.
4. The two identical masses are placed symmetrically on either side of the
suspension wire as close as possible to the centre of the disc, and measure
d1 which is the distance between the centres of the disc and one of the identical
masses.
5. Find the time for 20 oscillations twice and determine the mean period of
oscillation T1.
6. The two identical masses are placed symmetrically on either side of the
suspension wire as far as possible to the centre of the disc, and measure d2 which
is the distance between the centres of the disc and one of the identical masses.
7. Find the time for 20 oscillations twice and determine the mean period of
oscillation T2.
8. Find the moment of inertia of the disc using the given formulae.
16
Observations:
1. Length of the suspension wire = ................m
2. Radius of the suspension wire = ..............m
3. Mass of each identical masses = .............kg
4. d1 =...........m
5. d2 =...........m
Observation Table:
Length of the
suspension wire l
(m)
Time for 20 oscillations (in seconds) Period of
oscillations (in seconds)
Without mass With masses at
d1 With masses at
d2 T0 T1 T2
1 2 Mean
(T0) 1 2
Mean (T1)
1 2 Mean
(T2)
Calculations:
Moment of inertia of the given disc, I0 = 2 m (d22
– d12)
–
Result:
The moment of inertia of the given disc is ………………………… kg-m2
17
Shantilal Shah Engineering College, Bhavnagar
Physics Laboratory Manual
Experiment-7 (P_7)
Objective: Measurement of the distance using ultrasonic sensors
Procedure:
1. Connect the mains cord to the Trainer.
2. Switch ‘On’ the power supply.
3. Now select Clock Generator for frequency of 40 kHz at mode ‘2’.
4. Select second switch at “Distance Measurement” mode.
5. Adjust the Threshold Voltage such that the display shows exact reading of distance.
6. Take the reflector plate from the accessories box and hold it with the hands in the
Ultrasonic range.
7. Move the reflector plat up and down parallel to the ultrasonic sensors (Transmitter
and Receiver)
8. Observe the display as it shows the distance (in cm) between the ultrasonic sensors
and the object.
9. Note the reading of distance and compare it by taking a meter scale.
Note: Object should be placed more than 28cm far from the Ultrasonic sensors.
Result: The distance measured by ultrasonic sensors is ………………. m.
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